A commonly known air conditioning apparatus is configured as a result of a heat source unit having a compressor and a heat source-side heat exchanger, and a utilization unit having a utilization-side expansion valve and a utilization-side heat exchanger, being interconnected via a liquid refrigerant connection pipe and a gas refrigerant connection pipe. The properness of the quantity of refrigerant inside the refrigerant circuit of this air conditioning apparatus is determined by operating the air conditioning apparatus under a predetermined condition and detecting the degree of subcooling of the refrigerant in the outlet side of the heat source-side heat exchanger. As this operation under a predetermined condition, there is, for example, operation where the degree of superheating of the refrigerant in the outlet of the utilization-side heat exchanger functioning as an evaporator of the refrigerant is controlled such that it becomes a positive value and where the pressure of the refrigerant on the low pressure side of the refrigerant circuit resulting from the compressor is controlled such that it becomes constant (see Japanese Patent Publication No. 2006-023072).